Hydraulically powered derricks have long been used for many purposes as shown, for example, by U.S. Pat. Nos. 1,973,197 Baker and 3,474,924 Wheeler. However, as the depths to which wells must be drilled have increased, with a corresponding increase in the loads which must be handled by the derrick, workers in the well drilling art have recognized the need for increasing the strengths and load-handling capacities of well derricks and have proposed more massive and complex derricks as seen, for example, in U.S. Pat. Nos. 4,128,229 Elliston and 4,170,340 Mouton. Though the advantages of such derricks are recognized, there has been a continuing need for improvement, particularly in reducing costs and increasing versatility.